18131-25-4Relevant academic research and scientific papers
Structural and thermal gas desorption properties of metal aluminum amides
Ono, Taisuke,Shimoda, Keiji,Tsubota, Masami,Hino, Satoshi,Kojima, Ken-Ichi,Ichikawa, Takayuki,Kojima, Yoshitsugu
, p. 297 - 301 (2010)
Metal aluminum amides M[Al(NH2)4]x (M = K, Mg, and Ca; x = 1 and 2) were synthesized along with previously reported LiAl(NH2)4 and NaAl(NH2)4 by ball milling technique under liquid NH3. The profiles of synchrotron radiation X-ray diffraction suggest that KAl(NH2)4, Mg[Al(NH2)4]2 and Ca[Al(NH2) 4]2 have been indexed with single phases, which have never been reported so far. Combination of both FT-IR and 27Al MAS/3QMAS nuclear magnetic resonance suggest that they all have an anion complex unit [Al(NH2)4]- as a basic component, indicating successful synthesis of the metal aluminum amides. Thermogravimetry-differential thermal analysis coupled with mass spectroscopy showed the release of NH 3 below the temperatures of 140 °C during the thermal decomposition and a NH3 desorption peak temperature (Tdes) decreased with the increasing atomic number. Additionally, a relationship between 27Al isotropic chemical shift and Tdes was discussed. The present study gives an useful information that the thermal stability of the anion complex [Al(NH2)4]- can be controlled by a cation M.
Ternary amide-hydride system: A study on LiAl(NH2)4-LiAlH4 interaction
Chua, Yong Shen,Xiong, Zhitao,Wu, Guotao,Chen, Ping
, p. 597 - 601 (2019/03/26)
LiAl(NH2)4 is a ternary amide that readily decomposes to release ammonia at temperatures as low as ～ 90 °C. Owing to such instability as compared to binary amides, we hypothesize that the dehydrogenation mechanism involving ternary amide-hydride interaction would be significantly different from those of binary metal amide-hydride interaction. Therefore, in this study, interaction of LiAl(NH2)4 and LiAlH4 has been investigated by means of mechanical milling and thermal method. It was found that dehydrogenation occurred spontaneously during the milling process and the rate of dehydrogenation increased with increasing amount of LiAlH4, suggesting an ion migration mediated dehydrogenation. As reaction progressed, the formation of Li3AlH6 as an intermediate was detected and a total of 8 equiv. of H2 (7.5 wt%) can be released, forming LiH and AlN as the final product. In contrast, heating the homogenously ground LiAl(NH2)4 and LiAlH4 sample resulted in the release of NH3 at low temperatures, indicating that NH3 mediation would take place in case of dehydrogenation. Further increase in temperature resulted in a rapid release of hydrogen from the interaction of the LiAl(NH)2 and LiAlH4. It was also found that hydride with higher basicity is required to trigger amide-hydride interaction for dehydrogenation at low temperatures.
